The Effect of Cosmic Rays on Cometary Nuclei. I. Dose Deposition

Gronoff, G.; Maggiolo, R.; Cessateur, G.; Moore, W. B.; Airapetian, V.; De Keyser, J.; Dhooghe, F.; Gibbons, A.; Gunell, H.; Mertens, C. J.; Rubin, M.; Hosseini, S. (2020). The Effect of Cosmic Rays on Cometary Nuclei. I. Dose Deposition. Astrophysical journal, 890(1), p. 89. Institute of Physics Publishing IOP 10.3847/1538-4357/ab67b9

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Comets are small bodies thought to contain the most pristine material in the solar system. However, since their formation ≈4.5 Gy ago, they have been altered by different processes. While not exposed to much electromagnetic radiation, they experience intense particle radiation. Galactic cosmic rays and solar energetic particles have a broad spectrum of energies and interact with the cometary surface and subsurface; they are the main source of space weathering for a comet in the Kuiper Belt or in the Oort Cloud, and also affect the ice prior to the comet agglomeration. While low-energy particles interact only with the cometary surface, the most energetic ones deposit a significant amount of energy down to tens of meters. This interaction can modify the isotopic ratios in cometary ices and create secondary compounds through radiolysis, such as O2 and H2O2 (Paper II). In this paper, we model the energy deposition of energetic particles as a function of depth using a Geant4 application modified to account for the isotope creation process. We quantify the energy deposited in cometary nucleus by galactic cosmic rays and solar energetic particles. The consequences of the energy deposition on the isotopic and chemical composition of cometary ices and their implication on the interpretation of cometary observations, notably of 67P/Churyumov Gerasimenko by the ESA Rosetta spacecraft, will be discussed in Paper II.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute

UniBE Contributor:

Rubin, Martin

Subjects:

500 Science > 520 Astronomy
600 Technology > 620 Engineering
500 Science > 530 Physics

ISSN:

0004-637X

Publisher:

Institute of Physics Publishing IOP

Language:

English

Submitter:

Dora Ursula Zimmerer

Date Deposited:

05 Nov 2020 08:49

Last Modified:

15 Nov 2020 02:45

Publisher DOI:

10.3847/1538-4357/ab67b9

BORIS DOI:

10.7892/boris.147692

URI:

https://boris.unibe.ch/id/eprint/147692

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